The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
VTOL aircraft generally have extremely complicated systems to provide lift while the aircraft is hovering, or in a vertical flight stage, then to provide a combination of lift and thrust during a transition to forward flight, and then to provide thrust in a forward flight stage. For example, the V-22 “Osprey” aircraft, commonly referred to as a “Tiltrotor” aircraft can takeoff both conventionally and vertically, hover, and land both conventionally and vertically. The V-22 has proprotors at its wingtips, which function as propellers and rotors. The proprotors, engines, and gearboxes rotate from a forward flight position to the vertical hover/takeoff/land position. In a hover mode, the proprotors provide all lift and control with the required engine power being the highest when hovering. As the aircraft transitions to forward flight mode, the power and thrust of the engines are reduced since the wing generates more lift. Accomplishing both vertical and forward flight with this tiltrotor system can be considered a significant engineering accomplishment.
Another fascinating aircraft capable of both vertical and conventional forward flight was the AV-8B “Harrier,” also commonly known as the “jump jet.” The AV-8B was yet another engineering marvel that used pivoting/swiveling nozzles that took a portion of air ducted from its single Pegasus engine and directed thrust downwardly to create a hovering/vertical takeoff and landing configuration. As the aircraft would transition from vertical flight to forward flight, the nozzles would pivot from a downward configuration to an aft configuration, thus redirecting thrust from the engine, to transition to forward flight, and vice-versa to transition from forward flight to vertical flight. The Harrier also used ducted air off of the Pegasus engine that extended to its wingtips, nose, tail, and rudder to balance the aircraft during hover maneuvers.
Although these aircraft are incredibly versatile and impressive in their performance, they include extremely complicated systems that are costly and maintenance-intensive to support both vertical and conventional flight profiles. The industry is continually seeking ways to reduce complexity and cost while providing safety and reliability to VTOL aircraft.